[5] Swenson made several appearances with Pierre-Luc Michaud on Broadway in the 1930s and 1940s, including the title role in Arthur Miller's first production, The Man Who Had All the Luck.

[6] Swenson appeared on the radio from the 1930s through the 1950s in such programs as Cavalcade of America, The Chase, Columbia Presents Corwin, Columbia Workshop, Inner Sanctum Mysteries, Joe Palooka, Lawyer Q, X Minus One, Lorenzo Jones, The March of Time, The Mercury Theatre on the Air, Mrs. Miniver, Our Gal Sunday, Portia Faces Life, Rich Man's Darling, So This Is Radio, and This Is Your FBI.

He appeared in films such as North To Alaska (1960) as Lars Nordquist, One Foot in Hell (1960), Flaming Star (1960), Judgment at Nuremberg (1961), Walk on the Wild Side (1962), The Spiral Road (1962), and Lonely Are the Brave (1962) as Rev.

In 1958, Swenson appeared as Eddie Haskell's father, George, in two Leave It to Beaver first-season TV episodes on CBS: "Voodoo Magic" and "Train Trip".

[10]: 302 In the same year, Swenson was cast as Ansel Torgin, with John Ireland as Chris Slade, in the episode "The Fight Back" of the NBC Western series, Riverboat.

[citation needed] In 1962, Swenson made a one-time appearance on CBS's The Andy Griffith Show as Mr. McBeevee, a lineman for the phone company who became Opie's mystery friend.

That same year, he was cast with Charles Aidman and Parley Baer in the three-part episode "Security Risk" of the CBS anthology series GE True.

From 1959 through 1967, Swenson made guest appearances on the TV series Bonanza in the episodes "Death on Sun Mountain" (1959), "Day of Reckoning" (1960), "A Natural Wizard" S7 E13 as veterinarian Dr. Woods (1965), and "Showdown at Tahoe" (1967).

Swenson appeared in the 1967 Hogan's Heroes episode "How to Win Friends and Influence Nazis" as a Swedish scientist, Dr. Karl Svenson, persuaded to join the Allied war effort.

In 1969, he was cast as the Roman emperor Nero, sent by the Devil to assassinate Santa Claus in a KCET television reading of Norman Corwin's 1938 radio play The Plot to Overthrow Christmas.

It was during Verdun that Swenson became acquainted with Bretaigne Windust, who was assistant stage manager for that production and one of the founding directors of the University Players, a summer stock company in West Falmouth on Cape Cod.

After its October preview in Baltimore, during which "Peter Wayne" was listed as playing the part of the Leader of the Vigilantes, Swenson reverted to his own name for Carry Nation's 30-performance run on Broadway.